JPH03285551A - Brushless motor and fan employing brushless motor - Google Patents

Abstract

PURPOSE:To eliminate influence of heat on a rotor position detecting sensor by disposing a rotor position detecting disc at one end of a rotor shaft and disposing the rotor position detecting sensor, for outputting a detection signal in response to the rotational displacement of the rotor position detecting disc, oppositely to a surface facing with the outer part of the rotor position detecting disc. CONSTITUTION:A rotor position detecting disc 17 is fixed through a screw 16 to one end of a rotor shaft 8. A boss 19a having a central holder fixing hole 19, larger than the outer diameter of the rotor position detecting disc 17, is projected integrally outward from the center of the end wall of a frame 2. A circuit board 25 is provided at the boss part 19a. A rotor position detecting sensor part 26 is fixed at a position of the circuit board 25 opposite to the outside face of the disc 17.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a brushless motor used, for example, as a drive motor for a ventilation fan device, a vacuum cleaner, or as another power source, and a brushless motor using the motor. Regarding blowers.

(Prior art) For example, in a plusless motor used in a vacuum cleaner, etc., switching of energization to the stator windings is controlled.
It is trying to rotate the rotor.

By the way, in order to obtain information for controlling such switching of energization, a device for detecting the rotational position of the rotor is required.

Brushless motors use permanent magnets at both ends, and conventionally the rotational position of the rotor has been detected using the magnetic field of the permanent magnets. Specifically, a detection sensor such as a Hall element is provided near the rotor, and the detection sensor outputs a detection signal according to the rotational displacement of the rotor.

(Problem to be solved by the invention) However, the detection sensor has a drawback in that it is susceptible to the effects of heat.

However, the brushless motor used in vacuum cleaners and the like mentioned above has a high driving voltage of 100 to 200 VJ. Therefore, the detection sensor placed near the stator has to deal with the large amount of heat generated by the strong magnetic field. There is a risk that malfunction may occur due to the temperature rise.

This invention was made in view of the above circumstances, and its purpose is to provide a brushless motor that can prevent the influence of heat on a sensor for detecting the rotor position, and a blower using the motor. .

(Means for Solving the Problems) In order to achieve the above object, the brushless motor according to claim 1 provides rotor position detection at one end of a rotor shaft protruding outside from a stator housing space of a frame housing a stator. A rotor position detection sensor is provided opposite to the surface facing the outside of the rotor position detection disk and outputs a detection signal in accordance with the rotational displacement of the rotor position detection disk.

Further, in the blower according to claim 2, a rotor position detecting disk is provided at one end of the rotor shaft protruding outside from the stator storage space of the frame for storing the stator, and a rotor position detecting disk is provided on a surface facing the outside of the rotor position detecting disk. A rotor position detection sensor that outputs a detection signal in accordance with the rotational displacement of the rotor position detection disk is provided facing the rotor position detection disk, and a fan is provided at the other end of the rotor shaft on the opposite side to the rotor detection disk. It's what I did.

In the blower according to a third aspect of the present invention, an air exhaust path is formed from the air blower fan to the exhaust port through at least the stator housing space, and a rotor position detection sensor is disposed outside the air exhaust path.

The blower according to claim 4 forms a suction path outside the stator storage space from the suction port to the suction part of the blower fan,
The reason is that a sensor for detecting the rotor position is arranged in this suction path.

In the blower according to a fifth aspect of the present invention, the air exhaust path of the air blowing fan is configured to include a first air path that blows air from the blowing part of the blowing fan to the outside through the inside and outside of the stator storage space, and a first air path that is used for rotor position detection. and a second air path that blows out air to the outside through the sensor.

(Function) According to the brushless motor according to claim 1, the rotor position detection sensor is installed outside the stator storage space, which is farthest from the stator part where heat is generated and is not exposed to a high temperature atmosphere. , the thermal influence is small.

According to the blower according to the second aspect of the present invention, it is possible to provide a blower in which the rotor position detection sensor has little thermal influence.

According to the blower according to the third aspect, in addition to the above, the rotor position detection sensor is not affected by exhaust air containing heat from the stator.

According to the blower according to claim 4, in addition to the above, since the rotor position detection sensor is actively cooled by the low temperature suction air, it is possible to effectively prevent the temperature rise of the rotor position detection sensor. can.

According to the blower according to the fifth aspect, in addition to the above, the rotor position detection sensor can be cooled while minimizing heat conduction from the stator. In other words, it is possible to prevent the temperature of the rotor position detection sensor from rising due to heat conduction from the stator.

(Example) The present invention will be described below based on a first example shown in FIGS. 1 to 7. FIG. 1 shows a high-input, high-output inner rotor type drive motor that rotates at a high speed of 15,000 rpm or more and is used, for example, in a vacuum cleaner to which the present invention is applied.
The stator 2 and 3 are two in the front and back direction.
It is a cylindrical frame with a divided bottom. Frame 2, 3
The opening sides of are fastened together with screws 4. The internal space of these frames 2 and 3 is defined as a stator storage space 2a. The frames 2.3 are fitted to both ends of the stator 1, and the entire stator is housed in the stator storage space 2a.
It is stored in. Incidentally, as shown in FIG. 2, the winding 1b is wound so as to be capable of three-phase driving at a driving voltage of, for example, 100 to 200 VJ.

A ball bearing 5 is housed in the center of the end wall of one frame 2 via a bearing holder, which will be described later, and a ball bearing 6 is also housed in the center of the end wall of the other frame 3. The rotor 7 is then rotated by these pair of ball bearings 5.6.
is rotatably supported.

That is, the rotor 7 is formed from a rotor shaft 8 and a rotor body 9 mounted on the rotor shaft 8, as shown in FIGS. 3 and 5.

The rotor body 9 is formed by laminating a plurality of rotor body elements 9a, and each rotor body element 9a is formed from a permanent magnet 10 and a pair of rotor yokes 11.

The permanent magnet 10 has a disk shape that is magnetized along the axial direction, and has a center hole 10 through which the rotor shaft 8 passes through the center.
It has a. This permanent magnet 10 is a ferrite magnet or a rare earth magnet, and is formed by solidifying magnetic powder.

The pair of rotor yokes 11 have the same structure in terms of size and shape. These rotor yokes 11 have a part of the periphery of the yoke main part 12 that overlaps the side surface of the permanent magnet 10.
A cover portion 13 extending substantially perpendicularly to the yoke main portion 12 is integrally provided to form a cross-sectional shape. Note that the cover portion 13 is formed in an arc shape.

Further, a center hole 12a through which the rotor shaft 8 passes is formed in the center of the rotor main portion 12. Furthermore, each yoke main part 1
Circular protrusions 14 are integrally formed on the inner surfaces of the magnets 2, that is, on one side surface laminated to the permanent magnet 10. The inner diameter of the protrusion 14 is approximately equal to the diameter of the permanent magnet 10, and the side surface of the permanent magnet 10 is just fitted into the inner peripheral surface of the protrusion 14.

The pair of rotor yokes 11 are provided with yoke main parts 12 superimposed on both sides of the magnetized permanent magnet 10, so that the cover part 13 faces the outer circumferential surface 10b of the permanent magnet 10, and this outer circumferential surface It is provided to cover a part of 10b. Furthermore, the pair of rotor yokes 11 are laminated on both sides of the permanent magnet 10 so that the cover portions 13 thereof are arranged point-symmetrically with respect to the rotor axis 8, as shown in FIG.

The even number of motor main body elements 9a having the above configuration are mounted on the rotor shaft 8 in a stacked manner. Moreover, these laminated layers are arranged in a line-symmetrical arrangement with respect to a line extending perpendicularly to the axis of the rotor shaft 8 as a reference line. In other words, with rotor yokes 11 of different polarities stacked on top of each other,
Each rotor body element 9a is stacked. FIG. 3 shows the magnetism of each rotor yoke 11.

Note that the tips of adjacent rotor main body 90 cover portions 13 are separated from each other by a slight gap.

Each of these rotor body elements 9a is attached to the rotor shaft 8 by press-fitting the center holes 10a, 12a into the rotor shaft 8.

Further, a pair of adjustment members 15 and 15, which also serve as yokes, are attached to the rotor shaft 8, stacked on rotor yokes 11 located at both ends of the rotor shaft 8.

These pair of adjustment members 15.15 are used for adjusting rotational imbalance, and have a shape that reduces rotational imbalance, for example, a ring shape. Moreover, the adjustment member 15 is made of a non-magnetic material such as brass or 5US303.

Then, the balance can be adjusted by applying a process to reduce the rotational unbalance, for example, drilling a part of the side surface of the adjusting member 15 (the side surface not laminated to the rotor yoke 11), as necessary. ing.

Both ends of the rotor shaft 8 of the rotor 7 configured in this way are rotatably supported by the ball bearings 56, and the ball bearings 5,
It passes through 6. One end of the rotor shaft 8 that is located apart from between the ball bearings 5 and 6, that is, one end of the rotor shaft 8 that passes through the ball bearing 5 and projects outside from the stator storage space 2a, is provided with a first end. As shown in FIG. 6, a rotor position detection disk 17 is attached via a screw 16. For the disk 17, a thin disc-shaped magnet made of, for example, a combination of ferrite and resin is used. Magnetic poles are provided at predetermined intervals. Since this embodiment uses three-phase drive, eight magnetic poles are formed. Further, on the back surface of the rotor position detection disk 17, a disk support disk 18 which also serves as a back yoke is superimposed, as shown in FIGS. 6 and 7.

The inner periphery of this disc 18 is formed into a cylindrical shape that fits into the end of the rotor shaft 8. The end surface of this cylindrical portion 18a is in contact with the end surface of the inner ring of the ball bearing 5 on the disk 17 side.

On the other hand, at the center of the end wall of the frame 2, a boss portion 19a having a circular holder attachment hole 19 in the center that is larger than the outer diameter of the rotor position detection disk 17 is integrally provided to protrude outward. A bearing holder 20 is fitted into the holder mounting hole 19 so as to be movable along the thrust direction. The ball bearing 5 is housed in the center of the bearing holder 20, and the bearing holder 20 has a protruding wall portion 20a that protrudes in the direction of the rotor shaft 8.

This protruding wall portion 20a is connected to the disk 1 of the outer ring of the ball bearing 5.
It is in contact with the end face on the 7 side. Furthermore, holder mounting hole 1
A wall portion 21 is integrally formed on the inner surface of the spring bearing 9 on the opening side, and the spring bearing projects in the direction of the rotor shaft 8 . This wall portion 21 surrounds the outer periphery of the disk 17 and is provided apart from the peripheral side surface of the bearing holder 32. In these spring bearings, a ring-shaped thrust spring 22 made of a web washer or the like is sandwiched between the wall portion 21 and the bearing holder 20. The thrust spring 22 has the above-mentioned disk 1.
7 is used, and the disk 17 and disk support disk 18 are housed inside it.

This thrust spring 22 connects the bearing holder 20 to the stator 1.
This applies a thrust load to the outer ring of the ball bearing 5 in the direction of the other ball bearing 6 via the bearing holder 20. Also,
A pair of retaining rings 23 and 24 are attached to the rotor shaft 8.

One retaining ring 23 is in contact with the end surface of the inner ring of the ball bearing 5 on the stator 1 side, and the other retaining ring 24 is in contact with the end surface of the inner ring of the ball bearing 6 on the stator 1 side. Therefore, with these structures, the thrust load acts on the entire rotor 7, eliminating play between the inner and outer rings of each of the pair of ball bearings 5.6 and the poles.

Further, a circuit board 25 is provided on the boss portion 19a so as to close one holder attachment hole, with the outer surface of the protruding wall portion 20a as a mounting surface. In this installation, the circuit board 25 is installed in a position close to the disk 17. Note that the plate surface of the circuit board 25 corresponding to the screws 16 is open, and the screws 16 can be inserted through the opening.
can be operated. A sensor section 26 for detecting the rotor position is attached to a portion of the circuit board 25 facing the outer surface of the disk 17. This sensor section 26 uses, for example, a Hall element. Since the motor of this embodiment is driven by three phases, three are used. These sensor sections 26 and the disk 17 constitute a rotor position detection sensor that detects the rotational position of the rotor. In other words, the rotary position of the rotor can be detected in accordance with the detection signal output from the sensor section 26 in response to the rotational displacement of the disk 17. Then, based on this detection, energization to the winding 1b of the stator 1 is controlled via a control section (not shown), thereby causing the rotor 7 to rotate. Note that 27 is a shield plate attached to cover the external opening 19b of the boss portion 19a in which the circuit board 25 is housed. ! 125 is hidden from the outside.

On the other hand, at the other end of the rotor shaft 8 opposite to the disk 17, a blower fan, for example a centrifugal fan 28, is attached by screwing into the shaft end of a nut 29.

Further, an annular current plate 30 is provided on the outer periphery of the front end of the frame 3, located behind the centrifugal fan 28. The centrifugal fan 2 is mounted on the rectifying plate 30 and the protruding wall 31 on the outer periphery of the frame 3 that supports the rectifying plate 30.
A fan cover 32 is fitted to cover parts other than the central part of the fan 8. With these configurations, the centrifugal fan 28 forms a blower with the suction portion 33a at the center of the front surface and the outlet side at the outer periphery. Further, the wall portion of the baffle plate 30 on the rear side of the centrifugal fan 28 and the protruding wall 31 at the rear thereof are provided with openings for blowing air.
3b, the air can be blown out to the rear, that is, to the frame 2 side. The sensor section 26 is disposed outside the rear air exhaust path 34.

Thus, the blower configured in this manner controls the energization of the winding 1b of the stator 1 according to the rotational position of the rotor obtained by the detection signal output from the rotor position detection sensor section 26, and controls the stator 1. Winding 1 of
By sequentially switching the excitation phases b, the magnetic circuit formed between the stator 1 and the rotor body 9 rotates the rotor 7 at a high speed (15,000 rpm) or more.

As the rotor 7 rotates, the centrifugal fan 2
8 is rotationally driven to suck in air from the suction portion 33a on the front side and blow it out to the outer circumferential side.

Then, this blown air is blown out from the blowing portion 33b of the centrifugal fan 28 through the rectifying plate 30 and the protruding wall 31.

Here, the sensor section 26 is installed outside the stator storage chamber 2a, which is farthest from the stator 1 where heat is generated and is not exposed to the internal space of the frames 2 and 3, which is a high-temperature atmosphere. The impact will be small.

Therefore, it is possible to suppress a rise in temperature of the sensor section 26, and it is possible to improve reliability.

Furthermore, since the sensor section 26 is disposed outside the air exhaust path 34 of the centrifugal fan 28, it is not affected by the motor heat contained in the centrifugal fan 28, resulting in higher reliability.

In addition, since the ball bearings 5 and 6 are installed together with the sensor section 26 at the end of the frame farthest from the stator 1, which is the heat source,
Compared to the case where the ball bearings 5 and 6 are arranged inside the frame, the temperature rise of the ball bearings 5 and 6 can be suppressed. According to experiments, compared to a motor with bearings 5.6 placed inside frames 2 and 3, it was possible to halve the 2° degJ (absolute value of temperature rise). , 10"C, the temperature is lowered, so that the life of the grease in the ball bearing 5.6 can be improved and deterioration can be prevented, and the reliability of the bearing can also be improved together with the sensor section 26.

Further, the second invention is not limited to the first embodiment, but can be applied to the second embodiment shown in FIG. 8, the third embodiment shown in FIG. 9, and the fourth embodiment shown in FIG. Examples, a fifth embodiment shown in FIG. 11, a sixth embodiment shown in FIG. 12, a seventh embodiment shown in FIGS. 13 and 14, a fifth embodiment shown in FIGS.
An eighth embodiment shown in FIG. 6 may be used. However, FIGS. 8 to 14 are partially simplified drawings of the first embodiment.

That is, in the second embodiment, the ball bearing 5 is arranged inside the frame 2, and only the disk 17 and the sensor section 26 are arranged so as to largely protrude outside the stator storage space 2a.

The third embodiment is a modification thereof, in which the disk 17 and the sensor section 26 are arranged at a position where they do not protrude from the end wall of the frame 2. Even in this case, the same effects as in the first embodiment described above can be achieved.

Of course, it goes without saying that the position is not limited to that of this embodiment.

In the fourth embodiment, a cylindrical duct 40 with a bottom is inserted into the outer peripheral side of the frames 2 and 3 to form an air passage 41 that communicates with the blowout part 33b of the frame 2, and the bottom side of the duct 40 An air outlet body 42 extending in a direction perpendicular to the axis of the rotor shaft 8 is provided to protrude from the peripheral wall.

Further, an inlet side communication port 43 is provided in the peripheral wall on the end wall side of the frame 2 to communicate with the air outlet side of the fan chamber 28a.
An outlet side communication port 44 communicating with the air passage 41 is provided in the peripheral wall on the end wall side.

That is, the sensor section 26 is arranged outside the road as the exhaust path 34. Note that 42a indicates an outlet formed by the outlet body 42.

According to such an air exhaust path 34, the air blown out from the centrifugal fan 28 is divided into the fan storage space 2a and the air path 41. Then, as the blowing air crosses the fan storage chamber 2a, the stator 1 and the rotor 7 are cooled, and at the same time, the fan storage space 2a is ventilated to lower the ambient temperature. On the other hand, the blowing air that has entered the air passage 41 cools the stator 1 from the outside while flowing through the air passage 41. The cooled air and the air blown from the fan storage chamber 2a together move away from the air outlet body 42 from the center of the motor where the disk 17 and sensor section 26 are located. It is blown out in the direction.

According to this ventilation path structure, cooling from the inside and outside of the stator storage space 2a (the inside and outside of the motor) is performed from the stator 1 to the disk 17. Heat conduction to the sensor section 26 can be suppressed to a minimum, and a rise in temperature of the sensor section 16 can be effectively prevented.

The fifth embodiment is a modification of the fourth embodiment, in which the air inside and outside the stator storage chamber 2a is
Centrifugal fan 28
With the sensor section 26 facing the suction passage 28a, the sensor section 2
6 is not naturally cooled, but is forcibly cooled by the suction flow (low temperature air) of the centrifugal fan 28.

Specifically, in addition to the structure shown in the fourth embodiment, a suction duct 50 is provided across the suction portion 33a of the centrifugal fan 28, the outer peripheral portion of the duct 40, and the portion of the frame 3 where the sensor portion 26 is located. Further, the boss portion 19a is made to protrude into the suction path 51 formed by the suction duct 50, and the sensor portion 26 is arranged to protrude into the suction path 51. A suction port 52 is provided upstream of the sensor section 26.

According to such a structure, - layer, effectively the sensor part 26
temperature rise can be prevented.

The sixth embodiment is a modification of the fifth embodiment, in which the sensor section 2
6 is forcibly cooled not by the suction air of the centrifugal fan 28 but by the blowing air.

Specifically, in addition to the air exhaust path 34 (first air path) passing through the inside and outside of the stator 1 shown in the fourth embodiment, the blowing portion 33b of the centrifugal fan 28, the outer peripheral portion of the duct 40, A branch duct 60 (
A second air path) is provided to constitute an exhaust air path. Note that 60a is an air outlet.

In the seventh embodiment, the disk 17 is protected from the radial force generated by the high speed rotation of the motor.

That is, the disk 17 made of a combination of ferrite and resin has very low bending and tensile strength. Therefore, the disk 17 may be damaged by the radial force generated when the motor rotates at high speed. The force in the radial direction is also due to the fact that absolute balance cannot be obtained due to assembly errors, tolerances, etc. when attaching the thin disk 17 to the rotor shaft 8.

Therefore, as shown in FIGS. 13 and 14, in this embodiment, a protective peripheral wall 65 is provided on the outer peripheral portion of the disk support disk 18, and the protective peripheral wall 65 is fitted with the outer peripheral surface of the disk 17 attached to the disk support disk 18. The protective peripheral wall 65 also receives the force in the radial direction generated on the disk 17.

The eighth embodiment is a modification of the seventh embodiment, in which the disk 17 is protected from the force in the thrust direction generated by the high speed rotation of the motor.

Note that the force in the thrust direction is also caused by the fact that absolute balance cannot be obtained due to assembly errors, tolerances, etc. due to the thin disk 17 being attached to the rotor shaft 8.

That is, as shown in FIGS. 15 and 16, a ring-shaped fixing plate 66 having an outer diameter corresponding to the seat of the screw 160 is provided on the exposed surface side of the disk 17, and the disk 17 is fastened with the screw 16. The structure is such that the disk 17 is sandwiched between the fixing plate 66 and the disk supporting disk 18 using force. The fixed plate 66 receives the force in the thrust direction generated on the disk 17 and protects the disk 17 from the force in the thrust direction.

Note that the present invention is not limited to the embodiments described above.

For example, a rotor position detection sensor consisting of a rotor rotational position detection disk provided with slits at predetermined angles and an optical sensor may be used.

[Effects of the Invention] As explained above, according to the invention set forth in claim 1, the rotor position detection sensor is located in the stator storage space that is farthest from the stator portion where heat is generated and is not exposed to a high temperature atmosphere. Since it is installed outside of the building, the thermal influence is small.

Therefore, the temperature rise of the rotor position detection sensor can be suppressed.

Furthermore, according to the second aspect of the invention, it is possible to provide a blower in which the rotor position detection sensor has little thermal influence.

According to the third aspect of the present invention, in addition to the effect of the second aspect, the rotor position detection sensor is not affected by exhaust air containing heat from the engine.

According to the invention set forth in claim 4, in addition to the above, the rotor position detection sensor is actively cooled by the low-temperature suction air, so that a rise in temperature of the rotor position detection sensor can be effectively prevented. I can do it.

According to the invention set forth in claim 5, in addition to the above, the rotor position detection sensor can be cooled while minimizing heat conduction from the stator, and the rotor position detection sensor can be cooled by heat conduction from the stator. It can also prevent temperature rise.

[Brief explanation of drawings]

1 to 7 show a first embodiment of the invention,
FIG. 1 is a partially sectional side view showing a blower to which the present invention is applied, FIG. 2 is a plan view of the stator, FIG. 3 is a sectional view of the rotor, FIG. 4 is a side view of the rotor, and FIG. A partially exploded perspective view of the rotor, FIG. 6 is an enlarged cross-sectional view of the attachment part of the rotor position detection disk, FIG. 7 is an exploded perspective view, and FIG. 8 is a second embodiment of the present invention. FIG. 9 is a cross-sectional view showing the third embodiment of the present invention, and FIG.
FIG. 0 is a sectional view showing a fourth embodiment of the invention, FIG. 11 is a sectional view showing a fifth embodiment of the invention, and FIG. 12 is a sectional view showing a sixth embodiment of the invention. FIG. 13 is a sectional view showing the main parts of the seventh embodiment of the invention, FIG. 14 is an exploded perspective view, and FIG. 15 is a sectional view showing the main parts of the eighth embodiment of the invention. FIG. 16 is also an exploded perspective view. 1... Stator, 2, 3... Frame, 2a...
Stator storage chamber, 5.6... Ball bearing, 7... Rotor, 17... Rotor position detection disk, 25... Circuit board, 26... Rotor position detection sensor, 28.・
・Centrifugal fan.

Claims (1)

[Scope of Claims] 1. A stator, a frame provided on both sides of the stator and housing the stator, a rotor housed inside the stator, and a rotor axis of each rotor provided in each of the frames to be freely rotatable. a bearing supported by the frame; a rotor position detection disk provided at one end of the rotor shaft protruding from the stator housing space of the frame; and a rotor position detection disk provided opposite to a surface facing the outside of the rotor position detection disk. A brushless motor comprising: a rotor position detection sensor that outputs a detection signal in accordance with the rotational displacement of the rotor position detection disk. 2. a stator, a frame provided on both sides of the stator to house the stator, a rotor housed inside the stator, and a bearing provided in each of the frames to rotatably support the rotor shaft of the rotor; a rotor position detection disk provided at one end of the rotor shaft protruding from the stator housing space of the frame; and a rotor position detection disk provided opposite to a surface facing the outside of the rotor position detection disk. A blower comprising: a rotor position detection sensor that outputs a detection signal in accordance with rotational displacement; and a blower fan provided at the other end of the rotor shaft on the opposite side of the rotor position detection disk. . 3. Claim 2, characterized in that an air exhaust path is formed from the ventilation fan to the exhaust port via at least the stator housing space, and a rotor position detection sensor is disposed outside the air exhaust path.
The blower described in. 4. The blower according to claim 2, wherein a suction path is formed outside the stator housing space from the suction port to the suction portion of the blower fan, and a rotor position detection sensor is disposed in the suction path. 5. The ventilation path of the ventilation fan is from the blowing part of the ventilation fan,
It is characterized by being comprised of a first air path that blows out air to the outside through the inside and outside of the stator storage space, and a second air path that blows air out to the outside through a rotor position detection sensor. The blower according to claim 2.